(379e) Material Recycling of Polycarbonate from Electronic Waste Using Density Separation and Safer Solvents

Electronic Waste (E-waste) is an ever-growing waste stream. Containing components from a variety of electronics, current recycling rates for the waste stream are less than 20%. The majority of the waste is either landfilled or incinerated, creating issues around public health, environmental damage, and sustainability. Flame retardants, and other highly toxic substances found within the waste can leach into the surroundings when landfilled, polluting local water sources and ultimately the ecosystem. When incinerated, flame retardants are released uncontrollably into the atmosphere, with the likelihood of dioxin formation. To help improve electronic waste recycling rates, research focused on the following concepts:

1. Usage of density separation with salt water to cost-effectively separate different types of plastic found in electronic waste
2. Identification of safer solvents and anti-solvents for the material recycling of Polycarbonate (PC) from electronic waste plastics utilizing Hansen Solubility Parameter (HSP) theory

This study showed that density separation could be used to effectively sort ESR before solvent-based processing, with PC able to be more easily separated from the waste than other polymers. The solubility of a PC feedstock found in E-waste was measured and quantified using HSP theory. Dissolution screening indicated N-Methylpyrrolidone (NMP) as an effective safer solvent to fully dissolve the PC feedstock. Anti-solvent screening indicated water as a safer anti-solvent to be used with NMP. Preliminary precipitation testing validated the results from the anti-solvent screening, with water shown to be capable of recovering polymeric yields of over 80%. The results from this research indicate the potential of density separation followed by solvent-based processing for the recycling of PC from electronic waste for future reuse. Future research includes thermal, polymeric, and chemical characterizations of the recovered PC. The findings from this research will be valuable towards the recycling of other polymeric types found in electronic waste as well.